Tylenol in Pregnancy May Lower Testosterone in Unborn Boys


The study was conducted on mice with grafts of human tissue. The researchers tested the effect of paracetamol on testosterone production in mice with grafts of human testicular tissue which was designed to imitate how testes develop and function in pregnancy.

Rod Mitchell, a clinical research fellow at Edinburgh University, the lead research and his team s team gave the mice a standard daily dose of paracetamol over a period of either 24 hours or seven days. Then, they measured the amount of testosterone produced by the human tissue an hour after the final dose of paracetamol.

The results showed that after 24 hours of treatment that included Paracetamol, there was no effect on testosterone’s production. However, a week’s Paracetamol treatment led to a significant fail in testosterone’s production by 45%. Testosterone in men is of extreme importance for life-long health. Decreased exposure to testosterone in the womb is associated with increased risk of infertility, undescended testicles, and testicular cancer.

According to Rod Mitchell the results of this study only prove that regular intake of Paracetamol during pregnancy can increase the risks of various reproductive disorders in male babies.

Read Also: Causes and Treatments of Testicular Pain

Rod Mitchell said: “We would advise that pregnant women should follow current guidance that the painkiller be taken at the lowest effective dose for the shortest possible time.”

Tylenol in Pregnancy May Lower Testosterone in Unborn Boys

Paracetamol, also known as Tylenol in the United States, is one of the most common medicines. It is used to ease pain, reduce fever, and it is used routinely during all stages of pregnancy.

Sadaf Ghaem-Maghami, chair of the Royal College of Obstetricians and Gynaecologists’ scientific advisory committeem said the research was strong and had produced significant results. However, considering it was in animals with human tissues, it was rather difficult to estimate its meaning for humans.

She said: “Further research needs to be conducted into how paracetamol may affect testosterone levels.”

In her statement, Sadaf Ghaem-Maghami, added that pregnant women should continue to follow guidelines and take the Paracetamol of smallest effective dose for the short period of time and only when it’s necessary.

The study was published in the journal Science Translational Medicine and it is funded by the Wellcome Trust, the British Society of Paediatric Endocrinology and Diabetes and the Medical Research Council.

Low testosterone is defined as 300ng/dl (nanograms per deciliter) of total testosterone, and less than 5ng/dl of free testosterone (amount of hormones that is not connected to other proteins).

Approximately, one out of four men above 30 has decreased testosterone level.

The study shows once again that what pregnant women use during pregnancy can have a great impact on their children as well. However, even though regular Paracetamol/Tylenol intake can cause low testosterone level and cause reproductive problems later in life, it does not mean women can’t take this medicine at all. The researchers stressed the lowest amount is enough as long as it’s not taken on daily basis.


  • http://www.theguardian.com/lifeandstyle/2015/may/20/paracetamol-use-pregnancy-male-foetus-testosterone-study
  • http://www.heraldscotland.com/news/health/paracetamol-in-pregnancy-could-affect-unborn-boys-finds-study.126629679

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Expert Author : Syeda Kiran Zahra Hussain (Consumer Health Digest)

Syeda Kiran Zahra Hussain is a Pakistan origin health writer and nutritionist. After her basic education in Pakistan she moved to Oman for further studies and became "the First-Health Coach from the Sultanate". She is graduate of Psychology, Philosophy and English Literature, and was also nominated for "Full-Bright Scholarship Program," from St. Joseph College for women. Syeda is our lead contributing News Editor and she believes "Food is the best form of Preventive-Medicine".